TAMPA -- Long two points they badly needed was bad enough for the Tampa Bay Lightning. Potentially losing their starting goaltender would be worse.

Ottawa completed a sweep of the four-game season series as Milan Michalek scored three times in the third period of a 7-3 win at the Tampa Bay Times Forum on Tuesday night. Michalek scored a third-period power-play goal that restored Ottawa's two-goal lead, then added a pair of empty-netters for his second career hat trick.

But the home loss, disappointing as it was, may have cost the Lightning more than just two critically needed points.

Starting goaltender Mathieu Garon left the game with a lower-body injury just 3:54 into the opening period and did not return. Garon sustained the injury as he extended full-out to stop a shot. He had won six of his last seven decisions, helping the Lightning climb within four points of eighth-place Winnipeg entering Tuesday's game. He is scheduled for an MRI on Wednesday.

"It was tough seeing Garon get hurt," said center Steven Stamkos, whose League-high 48th goal made it 4-3 early in the third period but was in the box for Michalek's first goal. "He's been playing so well for us; he's given us a chance to win a lot of hockey games recently, so when he went down, obviously that's a blow. We were asleep the first period. There's no one to blame but ourselves."

Tampa Bay may have been asleep for the first 20 minutes, but the Lightning came alive during the next 20 minutes and made a game of it, cutting the Ottawa lead to one goal as Ryan Shannon scored his third of the season at 1:24 of the second period and Tim Wallace beat newcomer Ben Bishop at 7:12 for his second goal in the last two games. Tom Pyatt picked up assists on both scores.

Ottawa stopped the Lightning surge and regained a two-goal lead at 11:58 when Erik Karlsson, the NHL's highest-scoring defenseman, popped a rebound past Roloson for an unassisted power-play goal. The goal marked the 10th time in the last 12 games that the Senators got a goal from their defense.

Greening and Lightning defenseman Keith Aulie battled each other to an extended draw midway through the period. For Greening, who also picked up an assist on Gonchar's first-period score to go along with his own goal, it marked his first-ever Gordie Howe hat trick.

"Yeah, the guys kind of let me know between periods," Greening said. "It's not something I'm used to. But it is what it is, and it's just something that happened in the game."

The Lightning had won each of their last two games after trailing through two periods, and they made it exciting again when Stamkos scored on the power play at 5:41 of the final period. Teddy Purcell was credited with an assist to extend his point streak to ten games, a team-high for the Lightning this season.

But this time, the comeback came to a halt when Stamkos was sent off for goaltender interference after a scramble in the crease and Michalek scored on the ensuing power play.

"I didn't even think there was any contact on that play," Stamkos said about the penalty call. "I don't know what the ref saw. The puck was there; I actually had a pretty good scoring opportunity and thought the puck was in the net."

The loss stopped Tampa Bay's home winning streak at five and pulled the Senators (35-25-8) out of a two-game losing stretch. They return home to Ottawa to face the New York Rangers on Thursday.

"I thought we got off to a really good start in getting ahead 3-0," Ottawa coach Paul MacLean said. "We knew they'd have a response in the second period, and they did. I thought in the third period, we did a good job at taking care of business and brought the game home."

The three goals give Michalek a career-high 32.

"That's great for him," MacLean said. "I think he's always been a player of that potential and the injuries that he's had kind of slowed him down. We're really happy for him. To reach that plateau, it's really a credit to him and his hard work."

Bishop, acquired from St. Louis at the trade deadline, stopped 25 shots for his first win with the Senators.

"It was good," Bishop said. "We won. The guys played good in front of me and it's a bounce-back win for us after losing a couple. I got more comfortable as the game went along and it was my first NHL game in about a year."

Senators defenseman Chris Phillips left in the first period with a broken nose after a center-ice hit.

"Right now, it's open to evaluation," MacLean said of whether Phillips will be available for Thursday's game. "He had to get it reset. We'll just to see how he gets through it."

The Lightning (31-29-6) can't dwell on the loss -- not with a visit to division rival Washington next up on Thursday night.

"We need to start another streak now," Pyatt said. "There are a lot of games; we need to get another streak going."